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    <title>Document</title>
    <script>
        var number = prompt('请输入您需要的操作：\n 1.存钱 \n 2.取钱 \n 3.显示余额 \n 4.退出');
        var money = 100;
        while (number != 4) {
            if (number == 1) {
                var saving = prompt('请输入存的金额：');//saving存钱
                money += parseFloat(saving);
                alert('您现在的钱数是：' + money);
            }
            if (number == 2) {
                var take_Money = prompt('请输入取的金额：');//取钱
                money -= parseFloat(take_Money);
                alert('您现在的钱数是：' + money);
            }
            if (number == 3) {
                alert('您现在的钱数是：' + money);
            }
            var number = prompt('请输入您需要的操作：\n 1.存钱 \n 2.取钱 \n 3.显示余额 \n 4.退出');
        }
    </script>
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